Many kinds of removable band-type couplings for pipes exist in the art. It is noted that throughout the specification and claims, the term “pipe” encompasses any kind of generally cylindrical object, and the terms “clamp” and “coupling” are used interchangeably.
Pipeline leakage must be prevented for both economic and environmental reasons, depending on the nature of the fluid being transported. When needed repairs are inevitably carried out under field conditions, and in many situations there is a requirement that the flow of fluid in the pipeline may not be interrupted for any reason. Thus replacement of a faulty pipe joint is not an option.
Prior art seals are not capable of being used externally over an existing coupling or existing bell joint. Prior art seals lack the internal space needed if the repair seal is to be applied over and around an existing but leaking pipe joint. A further problem with many prior-art seals arises when the fluid being transported is under high pressure. This results in the seal lips being gradually pushed outwards, eventually leading to complete seal failure.
A solution to the above problems are split seal encapsulation pipe repair assemblies. The encapsulation seal assembly fits over existing bell-shaped joints, sleeve joints and the like, and seals the joint. The encapsulation seal assembly includes two metal half-rings that are bolted together at top and bottom flanges of the half-rings. Two elastomeric sealing half-rings are permanently attached to the inside of the two metal half-rings, and these sealing half-rings are clamped on both sides of the leak to stop the leak.
A challenge that faces all encapsulation seal assemblies is the seal must not only withstand radial forces but also axial forces (along the axial length of the pipes) that are created by the force of the fluid flowing through the joints that seal the pipes. These forces tend to urge the seal away from the pipe surface, which can cause leakage.